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Transient chaos is very common in periodically forced dynamical systems, but transient strange nonchaotic dynamics have not been studied by researchers. Therefore, it is meaningful to explore the dynamical phenomena of transient chaos and transient strange nonchaos. In this paper, we investigate a quasiperiodically forced cantilever beam system with impacts and discover abundant transient dynamic phenomena. Firstly, we determine the transient interval by the bifurcation diagram and the maximum Lyapunov exponent and investigate the correspondence between them. Secondly, we identify transient chaos and transient strange nonchaos and distinguish transient attractors and permanent attractors using the maximum Lyapunov exponent. Furthermore, we verify the strange property of attractors through the phase sensitivity and the power spectrum. [ABSTRACT FROM AUTHOR]

In this paper, we study strange nonchaotic attractors (SNAs) and multistable dynamics in a class of nonlinear economic systems. For quasiperiodically forced case, the generation and evolution mechanisms of SNAs are discussed. The fractal, Heagy–Hammel, torus doubling, and intermittency routes to SNAs are identified. The Lyapunov exponent, phase-sensitive function and power spectrum are used to characterize the dynamical and geometrical properties of SNAs. Moreover, when multistable phenomenon occur in the system, the boundaries of the basin of attraction may become intertwined, which leads to the economic unpredictability in the long run. [ABSTRACT FROM AUTHOR]

We study the improvement in the phase sensitivity of a Mach–Zehnder interferometer (MZI) using the superposition of 'Schrödinger's cat-like state with the vacuum state (SCVS)' and the vacuum state as inputs. With this setup, we examine the effect on the phase sensitivity of the interferometer using a parity detection scheme. We find better phase sensitivity under some conditions for this setup having potential application in quantum sensing. [ABSTRACT FROM AUTHOR]

We theoretically analyze the phase sensitivity of an SU (1 , 1) interferometer with various input states by product detection in this paper. This interferometer consists of two parametric amplifiers that play the role of beam splitters in a traditional Mach–Zehnder interferometer. The product of the amplitude quadrature of one output mode and the momentum quadrature of the other output mode is measured via balanced homodyne detection. We show that product detection has the same phase sensitivity as parity detection for most cases, and it is even better in the case with two coherent states at the input ports. The phase sensitivity is also compared with the Heisenberg limit and the quantum Cramér–Rao bound of the SU (1 , 1) interferometer. This detection scheme can be easily implemented with current homodyne technology, which makes it highly feasible. It can be widely applied in the field of quantum metrology. [ABSTRACT FROM AUTHOR]

This work elucidates the numerical simulations carried out for the performance analysis of surface plasmon resonance (SPR)–based fiber-optic sensors using thin layers of tantalum (v) oxide (Ta2O5) and graphene in phase interrogation scheme. For this purpose, fiber-optic sensing probes with three distinct configurations have been used which include consecutive as well as individual layers of Ta2O5 and graphene over silver-coated unclad core of a silica optical fiber. The performance of sensing probes is studied in terms of the phase difference arising between TM and TE polarized components of the incident light as they propagate through the sensing region, besides their SPR responses towards varying refractive index of analyte layer, making use of the transfer matrix theory for stratified isotropic optical media in conjunction with geometrical optics. Theoretical investigations reveal that the probe having multi-layered arrangement of Ta2O5 and graphene possesses maximum sensitivity of propagating phase difference with magnitude 4.852 × 105 Deg/RIU at analyte refractive index of 1.33 in comparison to probes with individual Ta2O5 (3.731 × 105 Deg/RIU) and graphene (0.362 × 105 Deg/RIU) layers. Moreover, the design parameters of the probes have been numerically maneuvered with an aim of achieving an analyte refractive index of 1.33 in transmitted light spectrum to display the feasibility of proposed sensor in biochemical fields. The reported results unfold an innovative perspective to widen the application horizon of fiber-optic SPR sensors in phase interrogation scheme. [ABSTRACT FROM AUTHOR]

Surface plasmon resonance (SPR) biosensor is widely used for its high precision and real-time analysis. In this paper, SPR biosensor based on the hybrid structure of metal–indium tin oxide (ITO)–WS2 are proposed and investigated. By optimizing the thickness of metals (Au, Cu, Ag), ITO and WS2, the reflectivity of 2.932 × 10−7 a.u and highest phase sensitivity of 1.711 × 106 deg/RIU are obtained by using Ag–ITO–WS2-dielectric structure. Compared with the traditional metal-based SPR sensor, the performance of the proposed one is improved up to ~ 25.8 times. The results show that ITO and WS2 have an important effect on enhancing SPR sensing performance. [ABSTRACT FROM AUTHOR]

In this paper, a surface plasmon resonance (SPR) sensor based on the hybrid structure of silver (Ag)-indium tin oxide (ITO)-graphene is proposed and investigated. SPR biosensors are subdivided into three kinds of structures Ag, Ag-graphene, and Ag-ITO-graphene, when carried out using their respective optimized structure parameters. According to our analysis and comparison, the ITO-assisted SPR biosensor has an optimal reflectivity of 3.587 × 10−8 and a maximum phase sensitivity of 1.707 × 106°/RIU, which shows that ITO can be employed to further enhance the SPR sensing performance even with the existence of graphene. [ABSTRACT FROM AUTHOR]

We propose a multi-mode nonlinear interferometer and study its phase sensitivity for two, three and four modes with single photons as inputs. We find that the phase sensitivity of the nonlinear interferometers can be improved by increasing the nonlinear index k. And when the total number of the input photons is fixed, increasing the number of modes is detrimental to the phase sensitivity. [ABSTRACT FROM AUTHOR]

We investigate the dependence of phase sensitivity and entanglement of two streams of photons that they incident upon Mach-Zehnder interferometer on the initial input states and the phase difference. Phase sensitivity and entanglement are periodic function of the phase difference. The initial input state with the more photons or smaller population difference induces the better phase sensitivity and entanglement. [ABSTRACT FROM AUTHOR]

We investigate the reciprocal of the mean quantum Fisher information per particle (RMQFIP) and phase sensitivity of atomic Josephson junctions with a bosonic species confined by a double-well potential. Here we are focus on the Rabi oscillation energy's influence on RMQFIP and phase sensitivity. The better quantum entanglement and phase sensitivity may be achieved by decreasing the Rabi oscillation energy. [ABSTRACT FROM AUTHOR]

We propose a scheme for preparing multi-photon entangled state which is useful for sub-shot-noise sensitivity with beam splitter, where the entangled degree is measured by the reciprocal of the mean quantum Fisher information per particle (RMQFIP). The multi-photon entangled state can be prepared by adjusting the transmissivity of the beam splitter and the better multi-photon entangled state can be prepared by increasing the total number of photons. [ABSTRACT FROM AUTHOR]

I investigate the dependence of phase sensitivity on the initial input states. By adopting frozen-spin approximation, I first derive the analytical expresses of the angular momentum operators and then of quantum Fisher information, the phase sensitivity. It is shown that the initial input state with smaller value of angular momentum has the better degree of entanglement and phase sensitivity beats the Heisenberg limit. [ABSTRACT FROM AUTHOR]

By using phase space method, we theoretically investigate the quantum statistical properties and quantum interference of optical parametric amplification of single photon. The statistical properties, such as the Wigner function (WF), average photon number, photon number distribution and parity, are derived analytically for the fields of the two output ports. The results indicate that the fields in the output ports are multiphoton states rather than single photon state due to the amplification of the optical parametric amplifiers (OPA). In addition, the phase sensitivity is also examined by using the detection scheme of parity measurement. [ABSTRACT FROM AUTHOR]

We investigate the phase sensitivity of a collection of interacting spins with quantum Fisher information controlled by an external field. By adopting the frozen-spin approximation, we derive the approximate analytical expressions of the maximal quantum Fisher information and the phase sensitivity. It is shown that the maximal quantum Fisher information and the phase sensitivity depend on the strength of the external field. With the increases of the external field, the period of oscillation of quantum Fisher information and phase estimation decrease, while the values of quantum Fisher information and phase sensitivity increase because of the suppress by the external field. [ABSTRACT FROM AUTHOR]

We investigate we investigate the quantum Fisher information and phase sensitivity in Yurke-like state superposed by two special multi-particle states and a symmetric state with relative phase. By studying the influences of superposition coefficients and relative phase on the maximal quantum Fisher information and phase sensitivity, we reveal some entanglement properties of Yurke-like state. [ABSTRACT FROM AUTHOR]

An echolocating bat produces echoes consisting of the convolution of echolocation call and the impulse response (IR) of the ensonified object. A crucial question in animal sonar is whether bats are able to extract this IR from the echo. The bat inner ear generates a frequency representation of call and echo and IR extraction in the frequency domain requires accurate analysis of both magnitude and phase information. Previous studies investigating the phase sensitivity of bats using a jitter paradigm reported a temporal acuity down to 10 ns, suggesting perfect sonar phase representation. In a phantom-target playback experiment, we investigate the perceptual phase sensitivity of the bat Phyllostomus discolor using a novel approach: instead of manipulating IR phase by changing IR delay (jitter paradigm), we randomized IR phase and thus lengthened the IR over time, leaving the magnitude spectrum unchanged. Our results show that phase sensitivity, as reflected in the analysis of signal duration, appears to be much lower than phase sensitivity, as reflected in the analysis of signal onset. The current data indicate that different temporal aspects of sonar processing are encoded with very different temporal resolution and thus an overall claim of “phase sensitivity” as such cannot be maintained. [ABSTRACT FROM AUTHOR]

The electric organ discharge (EOD) of the South American knifefish Eigenmannia sp. is a permanently present wave signal of usually constant amplitude and frequency (similar to a sine wave). A fish perceives discharges of other fish as a modulation of its own. At frequency identity (ΔF = 0 Hz) the phase difference between a fish's own electric discharge and that of another fish affects the superimposed waveform. It was unclear whether or not the electrosensory stimulus-intensity threshold as behaviourally determined depends on the phase difference between a fish's own EOD and a sine-wave stimulus (at ΔF = 0 Hz). Also the strength of the jamming avoidance response (JAR), a discharge frequency shift away from a stimulus that is sufficiently close to the EOD frequency, as a function of phase difference was studied. Sine-wave stimuli were both frequency-clamped and phase-locked to a fish's discharge frequency (ΔF = 0 Hz). In food-rewarded fish, the electrosensory stimulus-intensity threshold depended significantly on the phase difference between a fish's discharge and the stimulus. Stimulus-intensity thresholds were low (down to 3 μV/cm, peak-to-peak) when the superimposed complex wave changed such that the shift in zero-crossings times relative to the original EOD was large but amplitude change minimal; stimulus-intensity thresholds were high (up to 16.9 μV/cm, peak-to-peak) when the shift in zero-crossings times was small but amplitude change maximal. Similar results were obtained for the non-conditioned JAR: at constant supra-threshold stimulus intensities and ΔF = 0 Hz, the phase difference significantly affected the strength of the JAR, although variability between individuals was higher than that observed in the conditioned experiments. [ABSTRACT FROM AUTHOR]